1. Field of the Invention
The present invention deals with the field of devices for drying articles, particularly hydrophobic articles such as plastic flats or egg carrying trays. The present invention provides a means for drying of these flats which will most likely occur immediately after washing thereof which is a spin drying operation for centrifugally spinning the water or other cleansing solution thereof by high speed rotation of a stack of wet flats.
There are other means of drying such flats such as high speed air blowers or heated airstreams, however, spin drying has significant advantages in speed and in drying efficiency.
2. Description of the Prior Art
Many prior art devices have been utilized for the washing and drying of trays and egg carrying flats and other configurations have been utilized for spin drying of various articles such as shown in U.S. Pat. No. 2,609,100 patented Sep. 2, 1952 to S. L. Vitale on a xe2x80x9cDrying Machine Having Centrifugal Unitsxe2x80x9d; and U.S. Pat. No. 3,300,871 patented Jan. 31, 1967 to F. O""Conor and assigned to Ametek, INc. on a xe2x80x9cCentrifugal With Cover And Brake Assemblyxe2x80x9d; and U.S. Pat. No. 3,386,180 patented Jun. 4, 1968 to G. W. Balz et al and assigned to Roto-Finish Company on a xe2x80x9cContinuous Centrifugal Devicexe2x80x9d; and U.S. Pat. No. 3,998,656 patented Dec. 21, 1976 to L. P. Grotto on a xe2x80x9cMethod And Apparatus For Cleaning Cylindrical Air Filtersxe2x80x9d; and U.S. Pat. No. 4,064,635 patented Dec. 27, 1977 to H. Y. Kuhl on an xe2x80x9cApparatus For Drying Plastic Traysxe2x80x9d; and U.S. Pat. No. 4,134,215 patented Jan. 16, 1979 to H. Y. Kuhl on a xe2x80x9cProcess For Drying Hydrophobic Articlesxe2x80x9d; and U.S. Pat. No. 4,155,293 patented May 22, 1979 to A. Spiel et al and assigned to Nabisco, Inc. on a xe2x80x9cContinuous Cooking Apparatus And Processxe2x80x9d; and U.S. Pat. No. 4,170,241 patented Oct. 9, 1979 to J. W. M. Clapp and assigned to Thermoplastic Compounders Limited on an xe2x80x9cApparatus For Cleaning Containersxe2x80x9d; and U.S. Pat. No. 4,173,830 patented Nov. 13, 1979 to D. R. Hanson on a xe2x80x9cDryer For Mesh Basketsxe2x80x9d; and U.S. Pat. No. 4,651,440 patented Mar. 24, 1987 to G. M. Karl and assigned to Eastman Kodak Company on a xe2x80x9cSpin Drying Apparatusxe2x80x9d; and U.S. Pat. No. 4,702,777 patented Oct. 27, 1987 to H. Y. Kuhl on a xe2x80x9cMethod And Apparatus For High Capacity Washing, Sanitizing And Drying Of Stacks Of Flatsxe2x80x9d; and U.S. Pat. No. 5,067,192 patented Nov. 26, 1991 to F. Guelfi et al and assigned to Colged S.p.A. on an xe2x80x9cAutomatic Machine For Washing Self-Service Trays And Similar Itemsxe2x80x9d; and U.S. Pat. No. 5,185,041 patented Feb. 9, 1993 to R. M. Anderson et al on a xe2x80x9cMachine For Washing Plastic Fragments To Prepare Them For Recyclingxe2x80x9d; and U.S. Pat. No. 5,212,876 patented May 25, 1993 to B. I. Berit and assigned to Sanborn, Inc. on an xe2x80x9cAutomatic Spin Dryerxe2x80x9d; and U.S. Pat. No. 5,802,733 patented Sep. 8, 1998 to J. Hougham and assigned to The Great Norther Equipment Company on a xe2x80x9cDryer System For Vegetablesxe2x80x9d; and U.S. Pat. No. 6,298,575 patented Oct. 9, 2001 to J. E. Aikins et al on a xe2x80x9cPassive Spin Dryer For Continuous And Batch Processingxe2x80x9d; and U.S. Pat. No. Publication No. US 2002/0033550 A1 published Mar. 21, 2002 to K. Suehara on a xe2x80x9cMethod For Recycling Used-Up Plastic Products And Washing Process Of Crushed Plastic And Apparatus Thereforxe2x80x9d.
The present invention provides a unique apparatus for spin drying of a stack of flats including a housing which defines a base level therein at which level stacks of flats are transported for drying. The housing may also include a slotted wall extending circumferentially therearound to facilitate retaining of fluids expelled from the stack of trays during the spin drying operation itself. The slotted wall preferably is formed of a translucent material to facilitate observation of the operation of the apparatus for drying flats for monitoring and other reasons.
A lifting head is preferably included defined within the housing which is vertically movable to allow movement upwardly into contact with the undersurface of a stack of flats positioned thereabove at the base level to facilitate lifting thereof upwardly to a position above this base level. This higher position is referred to as the spin drying level. The lifting head is preferably movable rotatably relative to the housing about a lifting axis of rotation which extends vertically therewithin. The lifting head also includes a support plate preferably which is rotatably mounted therein and preferably includes a plurality of support pins extending vertically therefrom which are adapted to facilitate engagement of the support plate with respect to the undersurface of the stack of flats to facilitate retaining therein during upward movement.
A stack lifting device may be positioned within the housing at a location below the base level which is defined as the retracted position. This stack lifting device may preferably include an extensible pneumatic cylinder which urges movement of the lifting head upwardly into abutment with respect to the undersurface of a stack of flats at the base level for lifting thereof upwardly to the spin level for facilitating drying thereof when spun. The stack lifting device is preferably positionable at a retracted level below the base level within the housing in the normal steady state position. The stack lifting device is also preferably attached to the lifting head and is also vertically movable upwardly therewith to facilitate lifting of the head means into engagement with a stack of trays at the base level from beneath for lifting thereof vertically upward to a spin level for spin drying.
A drive engagement device is also preferably mounted within the housing at a position above a stack of flats positioned therein at the base level. This drive engagement device is mounted within the housing means to be rotatably movable therewith about a drive axis of rotation. This drive axis of rotation is preferably positioned below the lifting axis of rotation and is aligned vertically therewith to facilitate of the stack of flats during drying when engaged by the drive engagement device from above and the lifting means from below. Also the drive axis of rotation and the lifting axis of rotation are preferably oriented axially coincident with respect to one another.
The drive engagement device is adapted to engage a stack of flats from above responsive to movement of the stack of flats upwardly into abutting contact therewith in order to urge rotational movement of the stack of flats responsive to rotational movement of the drive engagement device. This device will include a spinner plate which is rotatable about the drive axis of rotation and is adapted to engage a stack of flats moved upwardly into contact therewith. The spinner plate preferably include a registration apparatus adapted to positively engage a stack of flats into contact therewith to provide simultaneous coordinated rotation of the stack of flats responsive to powered rotation of the drive engagement device. The registration apparatus will preferably include a plurality of alignment pins mounted in the spinner plate and extending downwardly therefrom to facilitate registration of the stack of flats with respect to the spinner plate for providing simultaneous rotational movement of the stack of flats responsive to powered rotation of the spinner plate. The alignment pins are preferably positioned in a pin array adapted to register with the stack of flats and cause same to rotate whenever the spinner plate is caused to rotate. The pin array preferably forms a rectangular profile to facilitate engaging of the corners of the stacks of the flats which are normally of rectangular shape.
A drive device is mounted within the housing above the stack of flats. The drive means is operatively attached to the drive plate for urging rotational movement thereof responsive to operation of the drive to spin dry a stack of flats held at the spin level between the drive engagement device in abutment therewith from above and the lifting head in abutment with the stack of flats from below. It is also urged into contact therewith by the stack lifting device being positioned at the spin level within the housing.
In the preferred configuration the drive device will include a spinner motor which rotationally drives the drive engagement device when necessary as well as a motor braking device to facilitate rapid slowing of the rotational movement of the stack of flats after the spin drying is concluded thereby facilitating prompt exiting thereof from the housing and speeding up the overall time required for the spin drying process. The braking device also aligns the stack of flats with the conveyor prior to replacement thereon after conclusion of spin drying. A stack conveying device is also preferably included for transporting stacks of trays into and out of the drying station at the base level.
This apparatus in operation is useful for spin drying of flats such as egg trays in accordance with a new improved novel process. This process includes the transporting by conveying of a stack of flats for entry into the spin drying housing at the base level. The stack of flats is then engaged from below by a rotatable lifting head. It is lifted upwardly by lifting the lifting head and the stack of flats engaged thereabove into abutting engagement with a drive engagement device positioned thereabove at the spin level above the base level within the drying housing. The drive engagement device is then registered with respect to the stack of flats to facilitate simultaneous rotation thereof responsive to rotation of the drive engagement device. The registering of the drive engagement device with respect to the stack of flats is performed preferably by including a plurality of alignment pins arranged in a pin array extending downwardly therefrom in position peripherally about the stack of flats abutting the drive engagement device from beneath. In this manner simultaneous rotation thereof with the drive engagement device will be achieved wherein the pin array includes two pins positioned peripherally at each of the four corners to facilitate engagement of the drive engagement device with respect to the rectangular stack of flats.
Thereafter the drive engagement device is rotationally driven to cause simultaneous rotational movement of the stack of flats for spin. drying thereof and cause simultaneous driving of the lifting head wherein the axis of rotation of the rotatable lifting head and the axis of rotation of the drive engagement device are parallel and vertically coincident with respect to one another. In this manner spin drying of the stack of flats held therebetween will be significantly facilitated. The rotational driving of the drive engagement device will also include a first rotational driving of the drive engagement device and stack of flats engaged therebeneath for drying thereof. Thereafter the drive engagement device and the stack of flats therebeneath will be subject to braking to rapidly cease rotational movement and align the stack of flats after spin drying with the conveying means located therebelow. Preferably thereafter there will be hesitation for a predetermined time period after braking for the purpose of allowing cleansing solution to drain from the stack of flats from areas therewithin which tend to accumulate liquid during spin drying. Thereafter a second rotational driving will be initiated of the driving engagement device and the stack of flats engages therebeneath to facilitate further drying of the stack of flats. The lifting head will then be moved downwardly with the stack of flats thereabove to release the stack of flats at the base level and allow the lifting head to move downwardly to the retracted position. The stack of flats will then be exit conveyed at the base level from the spin drying housing.
It should be appreciated that the apparatus of the present invention can be utilized in multiple immediately adjacently placed lines. For example the process and apparatus of the present invention can be utilized for spin drying of stacks of flats in a single feed line however it has been found more efficient to operate as many as two, three, four or even more lines immediately adjacent to one another for high speed drying of stacks of flats within a relatively small area which greatly facilitates monitoring of the equipment and high speed spin drying of the flats. It is also possible that the spinning of the flats which is defined above to occur twice could occur only once or could occur more than two times depending upon the tendency of the particular shape of flats to define capture spots which are areas that tend to accumulate liquid during spin drying.
It should be appreciated that the apparatus of the present invention is designed to be positioned immediately adjacent to a washer and preferably downstream therefrom. These washers for flats such as egg trays normally wash the flats when oriented singly upon a conveyor. The flats then need to be stacked to facilitate and significantly enhance the speed of spin drying thereof.
In operation of the apparatus of the present invention it is important to assure that a stack is not conveyed into the spin drying housing until after the stack which is currently being spin dried has exited therefrom. As such the present invention preferably includes a stack exit sensor positioned immediately adjacent the conveyor immediately downstream from the spin drying housing for the purpose of indicating that the housing no longer contains a stack of flats therein. This stack exit sensor is coordinated with a stack holding means adjacent the conveyor immediately upstream of the spin drying housing. This stack holding means is operative to stop the conveying of a stack of flats until an indication is rendered by the stack exit sensor that the stack of flats currently in the spin dryer has exited.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays which can be efficiently operated in as many as four or more immediately adjacent washing and drying lines for increasing maintenance capability and minimizing the use of floor space.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays which is particularly usable for removing water and cleaning solution from flats immediately after washing thereof.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays which provides a very high speed process for drying of trays since multiple trays in a stack are spun simultaneously.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays which can be utilized with any type of device immediately upstream therefrom for forming the flats into vertically extending stacks.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays which provides a fail safe method for preventing the movement of a stack of flats into the spin drying housing if a stack of flats is already present therewithin.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays wherein the stack of flats is lifted upwardly by a rotatable lifting means into registration and engagement with a spinner plate thereabove wherein the spinner plate is driven to facilitate spin drying of the stack of flats at an elevated position within the housing.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays wherein a slotted wall of transparent flexible material is positioned about the housing to minimize the exiting of any liquid expelled during spin drying from exiting the housing.
It is an object of the present invention to provide an apparatus for spin drying a stack of flats which is particularly usable for spin drying hydrophobic egg holding trays wherein the vertical lifting means for moving of the stack of flats upwardly into engagement with the spinner plate thereabove is powered by a pneumatic cylinder means.